1. Field of the Invention
The present invention relates to the field of testing parallel optical communication transmitters.
2. Background Information
To test Bit Error Ratio (BER) on all channels of a parallel optical communication transmitter, all channels must be exercised. Such testing requires equipment that includes a single data generator and data detector, and they must be switched to each input and output of a laser driver chip until all channels are tested, or in the alternative the test equipment must include multiple data generator/detectors.
In an attempt to solve the problems described above, an on-chip parallel data generator, including a Built In Self Test (BIST) parallel data generator, is integrated into the transmitter so that all optical outputs may be switched synchronously. The BIST generator requires only one clock input which clocks the BIST generator for all channels. However, a problem still exists because when asynchronous BER testing is desired, the electrical inputs cannot be used for any other testing since the parallel inputs of the chip are ignored during BIST operation.